Utility for shell-style file tests.
file_test(op, x, y)
- a character string specifying the test to be performed.
Unary tests (only
xis used) are
"-f"(existence and not being a directory),
"-d"(existence and directory) and
"-x"(executable as a file or searchable as a directory). Binary tests are
"-nt"(strictly newer than, using the modification dates) and
"-ot"(strictly older than): in both cases the test is false unless both files exist.
- x, y
- character vectors giving file paths.
‘Existence’ here means being on the file system and accessible
stat system call (or a 64-bit extension) -- on a
Unix-alike this requires execute permission on all of the directories in
the path that leads to the file, but no permissions on the file
itself. For the meaning of
"-x" on Windows see
dir <- file.path(R.home(), "library", "stats") file_test("-d", dir) file_test("-nt", file.path(dir, "R"), file.path(dir, "demo"))